Evaporimeter or atmometer



C; G. BATES. EVAPdRIMETER 0R ATMOMETER. APBLiQATION FILED JUNE 3 1919.

1,332,659. Patented Mar.2,1920.

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INVENTOR.

A TTORNEY,

CARLOS G. BATES, 01 DENVER, COLORADO.

EVAPORIMETER OR ATMOMETER.

Specification of Letters Patent.

Patented Mar. 2, 1920.

Application filed June 3, 1919. Serial No. 301,590.

(FILED UNDER THE ACT OF MARCH 3, 1883, 22 STAT. I, 625.)

To all whom it may concern:

Be it known that I, CARLos G. BATES, a citizen of the United States, and an employee of the U. S. Department of Agriculture, and residing in the city and county of Denver, State of Colorado, have invented a new and useful Improvement in Evaporimeters or Atmometers, of which the following is a specification.

The object of this invention is to provide a means whereby evaporation is produced at a rate which will coordinate approximately with the rate of evaporation from plants under all possible variations of light, heat, wind and atmospheric conditions.

This object is accomplished by the inclosure of a moist linen wick between two layers of metal, the lower of which contains small openings, which permit the vapor formed in and on the surface of the wick to escape by its own pressure to the outer atmosphere, as it does from the leaf of a plant. All other evaporimeters, or atmometers, so far as known, expose the entire moistened surface to the atmosphere. Because of this difference, my invention is influenced by each of the various factors which contribute to evaporation more nearly like the plant than are other known evaporimeters. P

For a full understanding of the invention, reference is made to the following description and drawings, in which Figure l is a cross section ofthe improved evaporimeter.

Fig. 2 is a top view of the under metal disk F of Fig. 1, showing the perforations, disassociated from the other parts.

Fig. 3.is a perspective view of the cover, or upper metal layer, HN of Fig. 1, disassociated from the other parts.

' Fig. 4 is a perspective of the instrument with the outer shell K and upper metal layer, or cover,'HN removed.

Fig. 5 is a perspective view of the outer shell K removed from the other parts.

Corresponding and like parts are referred to in the following descriptlon, and indicated in all the accompanying drawings, bythe same reference characters. a

The measurements hereinafter referred to are not essential to the invention, but are preferred for the the instrument.

Referring to the drawings, the outer shell K is made of 24. gage brass, 5 inches in diameter and 3 inches deep, riveted and soldered at side seam. The bottom of the shell is spun with a inch flange L, to which the wall or side is soldered.

A represents the inner tank, 4 inches in diameter at the top, 3 inches in diameter at the bottom, and 2% inches deep, spun of copper so as to result in a gage of about 24, with a flange M at the top edge.

The top of the tank is made of two thicknesses, B and B, of 24 gage brass, each 5 inches in diameter; the lower thickness spun with a 9,; inch flange, and the upper thickness B spun with a crown of 3; inch and with a :1; inch flange C. The lower thickness fits'snugly inside the flange C of B, and the two flanges are soldered together with their edges flush, and the top thus assembled fits snugly over the wall or side of the outer shell K. To this top the inner tank A is soldered concentrically, the flange M being attached to the layer B so that the tank shell K.

An opening K, 4 inch in diameter, is made in the center of the top for the insertion of the brass tubing E, which is inserted so as to penetrate both thicknesses of the top and is securely soldered to both. For the purpose of filling the tank A with water, another perforation L, inch in diameter, is made through both thicknesses of the top at a point near the outer edge. In this perforation is inserted and soldered to both thicknesses of the top a brass tubing D, which extends slightly above the top B and which is threaded to receive the cap D.

The tube E is made of moderately heavy brass tubing, inch outside diameter, 4:} inches long, and projects 4 inches above the top B.

The disk F is made of 16 gage brass, 4.44 inches in diameter, and is securely soldered to the top of the tubing E which will come flush with its upper surface. The collar I is first threaded on to theupper end of the tubing E, for the purpose of reinforcing or supporting the disk F. The disk F is perpurpose of standardizing A is suspended inside the forated with 6% drill holes F, each inch in diameter, which must be out clean so as to leave no roughness on the disk. These perforations should be distributed as evenly as possible throughout the disk.

Two lugs G, from 1}; inch to inch in each dimension, are soldered to the underside of the disk F, at pointson the outer edge that aredirectly opposite each other. Each of the lugs G is drilled and threaded, so as to receive a inch machine screw J.

The upper metal layer, or cover, H is made of 20 gage brass, slightly more than 4144. inches in diameter, spun with a #3 inch flange N, turned at right angles to the main surface and gaged so as to fit closely over the edges of the disk F. Two slots-O are.

cutin the. lower edge of the fiangeN, at the points where such flange comes in contact with the two lu 's G, when the upper layer or cover H is fitted over the disk F. Theseitwo slots 0' should be just deep enough to admit the screws J. The two metal layers H and F are held securely together by i,- in'ch roundheaded machine screws J, which when in place, will engage the edges of the two slots 0. in the flange N and the two lugs G. The two metal layers If and F must beL-flat', in order that the linen wick when placed between them will be closely in contact with each.

All exterior surfaces of the apparatus, including both surfaces of the disk F, but not including any part of the tank A, are neatly and durably nickeled.

In. the operation of'the improved mecha nism, a stem wick P is placed inside of the tube E, extending from. the bottom of the inner tank A to the upper surface of: the disk F... A thin circular disk linen wick O is placed between the disk F and the cover I'Lsoas to come in contact with the upper portion of the stem wick P. The upper end of the stem wick P, where it comes in contact withthe linen. wick- O, is raveled and flattened out in the form of a-rosette. The stem wick P,.being in contact with the water placed in the inner tank A, feeds thee-ircular wick O with moisture. The placing of. the circular wick 0 between the two metal layers H and F prevents the moist surface of the disk wick 0 being exposed directly to the outside air, and operates so that the" vapor formed in and on the surface of the'wic'k O is not immediately carried away by the air, but must be forced out by its own pressure, as it is from the leaf of the plant.

The seamless tank A is not injured by the freezing and thawing of the water in it, neithe-ris the linen wick affected by freezing,and this permits the operation of the instrument at all seasons without recourse to non-freezing solutions.

The outer shell or tank K, and the nickel plated surfacesthroughout, are designed to protect the reservoir and lower portions from radiant energy, consequently to restrict evaporation to the region of the disk wick 0. To accentuate evaporation at that point the metal. cover H is usually coated on the upper surface with lamp-black for the absorption of radial energy, and while this is not an essential feature of construction, it is essential to the most successful operation.

After the parts are assembled and the tank A filled with water the whole instrument is weighed. After a certain period of time: the instrument and contents are again. weighed and the difference in thetwo weights-determines the amount of evaporation produced.

I claim :1

1. An improvement in evaporimet'ers, including a layer of lineninclosed between two metal plates, one of which plates. contains perforations, and both of which are atta'ched,.by means of ametal tube,.to a closed seamless metal tank or reservoir, a linen wick extending through said tube and. into the seamless metal tank, which contains water, and connecting with the layer of linen between. the two metal: plates.

2. An improvement in evaporimeters, including a layer of linen inclosed between two metal plates, one of which plates. contains perforations, the: other of. which, in. combination. with lamp-black, is adapted. tovv the complete absorption of radiant energy, and thetransmitting of heatito' the layer of linen, and is so constructed. as to. exclude the moisture of precipitation from the layer of linen, both of which plates are attached, by means of metal tube, to a closed seamless metal tank containing water, a linen wick extending through such tube and into the seamless tank and connecting with the layer of linen between the two metal plates.

3. An improvementin evaporimeters, including a layer of linen between two metal plates, one: of which" contains. perforations, the other of which is: constructed with a flange so as to cover entirely the perforated plate and. the: layer of linen, and, in combination with lamp-black is adapted to the complete absorption of radiant energy and the transmission of heat to" the layer of linen, both of such plates being attached, by means ofa. metal tube,'to:- a" closed. seamless metal. tank, the layer of linen between the two metal plates being in contact with a rolled linen wick inclosed inrthe metal tube and: extendinginto the seamless metal tank, so that it willvcome in contact with water placed in the metal. tank andv will; transmit moisture to the linen layer between two metal plates;

4. An improvement in evaporimeters, consisting of a polished metal shell with a cover or top consisting of two layers of surface of the perforated disk, a metal plate 10 with a flange covering the layer of linen and the perforated disk, and held in place by machine screws engaging notches in the flange of said metal plate, and threaded lugs attached to the lower surface of the perfo- 15 rated disk at its edge.

CARLOS G. BATES. 

